Vascular endothelial growth factor serum level is strongly enhanced after burn injury and correlated with local and general tissue edema

Preconditioning strategies for improving the outcome of fat grafting

Autologous fat grafting is a common procedure in plastic, reconstructive and esthetic surgery. However, it is frequently associated with an unpredictable resorption rate of the graft depending on the engraftment kinetics. This, in turn, is determined by the interaction of the grafted adipose tissue with the tissue at the recipient site. Accordingly, preconditioning strategies have been developed following the principle of exposing these tissues in the pre-transplantation phase to stimuli inducing endogenous protective and regenerative cellular adaptations, such as the up-regulation of stress-response genes or the release of cytokines and growth factors. As summarized in the present review, these stimuli include hypoxia, dietary restriction, local mechanical stress, heat and exposure to fractional carbon dioxide laser. Preclinical studies show that they promote cell viability, adipogenesis and angiogenesis, while reducing inflammation, fibrosis and cyst formation, resulting in a higher survival rate and quality of fat grafts in different experimental settings. Hence, preconditioning represents a promising approach to improve the outcome of fat grafting in future clinical practice. For this purpose, it is necessary to establish standardized preconditioning protocols for specific clinical applications that are efficient, safe and easy to implement into routine procedures.

Heating Pretreatment of the Recipient Site Enhances Survival of Transplanted Fat in a Mouse Model

BACKGROUND

Despite several studies about the preparation of the recipient site in fat grafting, optimizing techniques with clinical usefulness is still necessary. Through previous animal studies reporting that heat can increase tissue vascular endothelial growth factor and vascular permeability, the authors hypothesize that pretreatment heating of the recipient site will increase retention of grafted fat.

METHODS

Twenty 6-week-old female BALB/c mice had two pretreatment sites on their back, one for the experimental temperatures (44°C and 48°C) and the other for the control. A digitally controlled aluminum block was used to apply the contact thermal damage. Human fat (0.5 mL) was grafted on each site and harvested on days 7, 14, and 49. The percentage volume and weight, histologic changes, and peroxisome proliferator-activated receptor gamma expression, a key regulator of adipogenesis, were measured by the water displacement method, light microscopy, and quantitative real-time polymerase chain reaction, respectively.

RESULTS

The harvested percentage volumes were 74.0% ± 3.4%, 82.5% ± 5.0%, and 67.5% ± 9.6% for the control, 44°C-pretreatment, and 48°C-pretreatment groups, respectively. The percentage volume and weight of the 44°C-pretreatment group was higher than the other groups ( P < 0.05). The 44°C-pretreatment group exhibited significantly higher integrity with fewer cysts and vacuoles than the other groups. Both heating pretreatment groups showed markedly higher rates of vascularity than the control group ( P < 0.017), and also increased the expression of peroxisome proliferator-activated receptor gamma over two-fold.

CONCLUSION

Heating preconditioning of the recipient site during fat grafting can increase the retention volume and improve the integrity, which is partly explained by increased adipogenesis in a short-term mouse model.

CLINICAL RELEVANCE STATEMENT

Tanning could be an alternative pretreatment for fat grafting.

Effects of resveratrol topical ointment on wound healing of full-thickness cutaneous burns in albino rats

OBJECTIVE

In this study, the effects of resveratrol topical ointment on wound contraction and histopathology of full-thickness cutaneous burn wounds were evaluated.

METHOD

Adult albino rats were grouped into four equal-sized groups of 15 rats each, as follows: Group A-no wound, no treatment (control); Group B-1% silver sulphadiazine; Group C-5% resveratrol, and Group D-wound without treatment (control). A burn wound measuring 23.5mm was created on the skin at the dorsum of all rats in groups B-D after shaving. The percentage of wound contraction was measured using a digital Vernier Caliper on days 1, 3, 5, 7, 10, 14, 16, 18 and 21, post-wounding. From each group, five rats were then euthanised and tissue samples of the skin, liver and kidney were collected in 10% buffered formalin for histopathology.

RESULTS

The percentage of wound contraction was significant (p<0.05) on 7, 14 and 18 days post treatment. Histopathologically, 5% resveratrol topical ointment application resulted in a thicker epidermis with neovascularisation and an increased collagen distribution. Resveratrol topical ointment ameliorated the extent of hepatocellular and nephrotubular injuries following burn-induced hepatocellular and acute kidney injuries.

CONCLUSION

In this study, topical application of 5% resveratrol ointment appeared to enhance burn wound healing by increasing the rate of wound contraction through collagen fibre synthesis, granulation tissue formation and epithelial regeneration.

Luteolin is an Effective Component of Platycodon grandiflorus in Promoting Wound Healing in Rats with Cutaneous Scald Injury

Background

Platycodon grandiflorus could significantly improve the pathological results of cutaneous scald injury, reduce the release of inflammatory factors and promote angiogenesis. This study investigated the wound healing effect of luteolin, an active component of P. grandiflorus, on induced cutaneous scald injury in Sprague-Dawley (SD) rats.

Methods

The protein expression levels of TNF-α and IL-6 were detected by ELISA. QRT-PCR was adopted to detect the expression of TGF-β1 and VEGF. Histopathological changes of scald wounds were analyzed by hematoxylin-eosin staining. Cell viability and migration ability were detected by CCK-8 assay and scratch assay.

Results

Both in vivo and in vitro experiments showed that luteolin promoted wound healing of cutaneous scald injury. Gene Oncology (GO) functional analysis and rescue experiments showed that endothelial nitric oxide synthase 3 (NOS3) was the critical target of luteolin in treating cutaneous scald.

Conclusion

This study demonstrated that luteolin is an effective component of P. grandiflorus and is effective in the treatment of cutaneous scald injury.

Platelet Priming and Activation in Naturally Occurring Thermal Burn Injuries and Wildfire Smoke Exposure Is Associated With Intracardiac Thrombosis and Spontaneous Echocardiographic Contrast in Feline Survivors

Wildfires pose a major health risk for humans, wildlife, and domestic animals. We previously discovered pathophysiologic parallels between domestic cats with naturally occurring smoke inhalation and thermal burn injuries and human beings with similar injuries; these were characterized by transient myocardial thickening, cardiac troponin I elevation and formation of intracardiac thrombosis. While the underlying mechanisms remain unclear, results from murine models suggest that platelet priming and activation may contribute to a global hypercoagulable state and thrombosis. Herein, we evaluated and compared the degree of platelet activation, platelet response to physiologic agonists and levels of platelet-derived microvesicles (PDMV) in 29 cats with naturally occurring wildfire thermal injuries (WF), 21 clinically healthy cats with subclinical hypertrophic cardiomyopathy (HCM) and 11 healthy cats without HCM (CC). We also quantified and compared circulating PDMVs in WF cats to CC cats. In addition, we examined the association between thrombotic events, severity of burn injuries, myocardial changes, and the degree of platelet activation in cats exposed to wildfires. Flow cytometric detection of platelet surface P-selectin expression showed that WF cats had increased platelet response to adenosine diphosphate (ADP) and thrombin compared to the two control groups indicating the presence of primed platelets in circulation. In addition, cats in the WF group had increased circulating levels of PDMV, characterized by increased phosphatidylserine on the external leaflet. Cats in the WF group with documented intracardiac thrombosis had elevated platelet activation and platelet priming in the presence of ADP. While high dose arachidonic acid (AA) mostly resulted in platelet inhibition, persistent response to AA was noted among cats in the WF group with intracardiac thrombosis. Univariate and multiple logistic regression analyses demonstrated that increased platelet response to AA was independently associated with thrombotic events. This is the first study reporting the significant association between platelet priming and intracardiac thrombosis in domestic cats with naturally occurring wildfire-related injuries and smoke inhalation. Further studies are required to delineate additional mechanisms between inflammation and thrombosis, especially regarding platelet primers and the cyclooxygenase pathway.

Stem Cell Therapy for Burns: Story so Far

Burn injuries affect approximately 11 million people annually, with fatalities amounting up to 180,000. Burn injuries constitute a global health issue associated with high morbidity and mortality. Recent years have seen advancements in regenerative medicine for burn wound healing encompassing stem cells and stem cell-derived products such as exosomes and conditioned media with promising results compared to current treatment approaches. Sources of stem cells used for treatment vary ranging from hair follicle stem cells, embryonic stem cells, umbilical cord stem cells, to mesenchymal stem cells, such as adipose-derived mesenchymal stem cells, bone marrow-derived mesenchymal stem cells, and even stem cells harvested from discarded burn tissue. Stem cells utilize various pathways for wound healing, such as PI3/AKT pathway, WNT-β catenin pathway, TGF-β pathway, Notch and Hedgehog signaling pathway. Due to the paracrine signaling mechanism of stem cells, exosomes and conditioned media derived from stem cells have also been utilized in burn wound therapy. As exosomes and conditioned media are cell-free therapy and contain various biomolecules that facilitate wound healing, they are gaining popularity as an alternative treatment strategy with significant improvement in outcomes. The treatment is provided either as direct injections or embedded in a natural/artificial scaffold. This paper reviews in detail the different sources of stem cells, stem cell-derived products, their efficacy in burn wound repair, associated signaling pathways and modes of delivery for wound healing.

A narrative review of changes in microvascular permeability after burn

Objective

We aimed to review and discuss some of the latest research results related to post-burn pathophysiological changes and provide some clues for future study.

Background

Burns are one of the most common and serious traumas and consist of a series of pathophysiological changes of thermal injury. Accompanied by thermal damage to skin and soft tissues, inflammatory mediators are released in large quantities. Changes in histamine, bradykinin, and cytokines such as vascular endothelial growth factor (VEGF), metabolic factors such as adenosine triphosphate (ATP), and activated neutrophils all affect the body’s vascular permeability.

Methods

We searched articles with subject words “microvascular permeability”, “burn” “endothelium”, and “endothelial barrier” in PubMed in English published from the beginning of database to Dec, 2020.

Conclusions

The essence of burn shock is the rapid and extensive fluid transfer in burn and non-burn tissue. After severe burns, the local and systemic vascular permeability increase, causing intravascular fluid extravasation, leading to a progressive decrease in effective circulation volume, an increase in systemic vascular resistance, a decrease in cardiac output, peripheral tissue edema, multiple organ failure, and even death. There are many cells, tissues, mediators and structures involved in the pathophysiological process of the damage to vascular permeability. Ulinastatin is a promising agent for this problem.

An Assessment of Research Priorities to Dampen the Pendulum Swing of Burn Resuscitation

On June 17 to 18, 2019, the American Burn Association, in conjunction with Underwriters Laboratories, convened a group of experts on burn resuscitation in Washington, DC. The goal of the meeting was to identify and discuss novel research and strategies to optimize the process of burn resuscitation. Patients who sustain a large thermal injury (involving >20% of the total body surface area [TBSA]) face a sequence of challenges, beginning with burn shock. Over the last century, research has helped elucidate much of the underlying pathophysiology of burn shock, which places multiple organ systems at risk of damage or dysfunction. These studies advanced the understanding of the need for fluids for resuscitation. The resultant practice of judicious and timely infusion of crystalloids has improved mortality after major thermal injury. However, much remains unclear about how to further improve and customize resuscitation practice to limit the morbidities associated with edema and volume overload. Herein, we review the history and pathophysiology of shock following thermal injury, and propose some of the priorities for resuscitation research. Recommendations include: studying the utility of alternative endpoints to resuscitation, reexamining plasma as a primary or adjunctive resuscitation fluid, and applying information about inflammation and endotheliopathy to target the underlying causes of burn shock. Undoubtedly, these future research efforts will require a concerted effort from the burn and research communities.

High Versus Low Volume Fluid Resuscitation Strategies in a Porcine Model (Sus scrofa) of Combined Thermal and Traumatic Brain Injury

BACKGROUND

Combined burn and traumatic brain injury (TBI) treatment priorities may not align due to opposing fluid resuscitation paradigms used in treating burns and TBI. We developed a porcine model of combined thermal injury/TBI and compared an "aggressive" fluid resuscitation strategy using the Parkland formula and a "restrictive" resuscitation strategy using the modified Brooke formula.

METHODS

Twenty-eight swine were deeply anesthetized and received a 40% total body surface area full-thickness burn injury and TBI. Swine were then randomized to receive restrictive or aggressive resuscitation for 8 h after which time animals were euthanized and necropsy was performed. Volume of brain injury was assessed after analyzing segmental slices of brain tissue.

RESULTS

There were no differences between the restrictive and aggressive resuscitation groups in blood pressure, heart rate, central venous pressure, intra-cranial pressure (ICP), or serum lactate levels after 8 h of resuscitation. Urine output was higher in the aggressive resuscitation group. The restrictive group had a significantly higher serum blood urea nitrogen (BUN) compared with baseline and compared with the aggressive group. There was no significant difference in size of brain injury between groups.

CONCLUSIONS

Both restrictive and aggressive resuscitation demonstrated adequate resuscitation at 8 h postinjury. Increased serum BUN in the restrictive group may be an indicator of early acute kidney injury, despite adequate urine output. Resuscitation strategy did not appear to affect ICP or the size of brain injury.

Ali R, Abd. Hamid R, Chang SK, Rahman MH, Zainal Z, Khaza’ai H. Temporal changes in the cell population and wound healing-related gene expression in deep partial-thickness burn wound model

Background

Burns are injuries that lie on the skin or other organic tissues caused by exposures to the heat, electricity, chemicals or ionizing radiation. The present study was carried out to record temporal changes in the cell population and wound healing-related gene expression in rats with deep partial-thickness burn.

Methods

Burn wound was induced on the dorsal part of Sprague-Dawley rats using temperature-regulated 20-mm wide aluminum head heating device. Animals were then sacrificed on days three, seven, 11, 14 and 21 post-burn, respectively. Half of the wounded skin tissues were dissected and fixed in buffered neutral formalin for Hematoxylin & Eosin (H&E) staining, and the other half were cut off and stored in − 20 °C for real-time PCR analyses.

Results

The number of adipose cells was found to be maximal on the 3rd day post-burn, and it gradually decreased over time and completely disappeared on day 11 post-burn. The maximum number of neutrophils were found to be on the 3rd and 14th day post-burn, while the maximum number of myofibroblasts were found on the 11th day post-burn. The number of lymphocytes did not change too much during the whole healing process. At the gene expression level, the expression pattern of inflammation-related genes including IL-6, TNF-α and iNOS were similar, which was found to be increased from day 3 to day 11 and decreased thereafter. Angiogenesis related genes including both VEGF-A and TGF-β1 showed a same expression pattern, both of which were slightly increased from day 3 to day 14 and smoothly decreased on day 21 post-burn. Matrix re-modeling related genes including MMP-2, TIMP-2 and Collagen-1 changed over time synchronously, where they all persistently increased from day 3 till day 14, then slightly declined on day 21 post-burn.

Conclusion

The present study revealed the changes in the cell population and expression profile of wound healing-related genes in deep partial-thickness burn, which could provide a cellular and genomic basis for the future research of burn injuries.

Skin tissue regeneration for burn injury

The skin is the largest organ of the body, which meets the environment most directly. Thus, the skin is vulnerable to various damages, particularly burn injury. Skin wound healing is a serious interaction between cell types, cytokines, mediators, the neurovascular system, and matrix remodeling. Tissue regeneration technology remarkably enhances skin repair via re-epidermalization, epidermal-stromal cell interactions, angiogenesis, and inhabitation of hypertrophic scars and keloids. The success rates of skin healing for burn injuries have significantly increased with the use of various skin substitutes. In this review, we discuss skin replacement with cells, growth factors, scaffolds, or cell-seeded scaffolds for skin tissue reconstruction and also compare the high efficacy and cost-effectiveness of each therapy. We describe the essentials, achievements, and challenges of cell-based therapy in reducing scar formation and improving burn injury treatment.

Study of negative pressure wound therapy as an adjunct treatment for acute burns in children (SONATA in C): protocol for a randomised controlled trial

BACKGROUND

Although negative pressure wound therapy (NPWT) is widely used in the management of several wound types, its efficacy as a primary therapy for acute burns has not yet been adequately investigated, with research in the paediatric population particularly lacking. There is limited evidence, however, that NPWT might benefit children with burns, amongst whom scar formation, wound progression and pain continue to present major management challenges. The purpose of this trial is to determine whether NPWT in conjunction with standard therapy accelerates healing, reduces wound progression and decreases pain more effectively than standard treatment alone.

METHODS/DESIGN

A total of 104 children will be recruited for this trial. To be eligible, candidates must be under 17 years of age and present to the participating children's hospital within 7 days of their injury with a thermal burn covering <5% of their total body surface area. Facial and trivial burns will be excluded. Following a randomised controlled parallel design, participants will be allocated to either an active control or intervention group. The former will receive standard therapy consisting of Acticoat™ and Mepitel™. The intervention arm will be treated with silver-impregnated dressings in addition to NPWT via the RENASYS TOUCH™ vacuum pump. Participants' dressings will be changed every 3 to 5 days until their wounds are fully re-epithelialised. Time to re-epithelialisation will be studied as the primary outcome. Secondary outcomes will include pain, pruritus, wound progression, health-care-resource use (and costs), ease of management, treatment satisfaction and adverse events. Wound fluid collected during NPWT will also be analysed to generate a proteomic profile of the burn microenvironment.

DISCUSSION

The study will be the first randomised controlled trial to explore the clinical effects of NPWT on paediatric burns, with the aim of determining whether the therapy warrants implementation as an adjunct to standard burns management.

TRIAL REGISTRATION

Australian New Zealand Clinical Trials Registry, ACTRN12618000256279 . Registered on 16 February 2018.

Induced Granulation Tissue but not Artificial Dermis Enhances Early Host-Graft Interactions in Full-Thickness Burn Wounds

BACKGROUND

Cellular grafts used for skin repair require rapid integration with the host tissue to remain viable and especially to nourish the epidermal cells. Here, we evaluated the responses in the split-thickness skin grafts (STSGs) grafted on three differently treated wound beds: directly on excised wound bed (EX), on an artificial dermal template (DT) and on granulation tissue (GT) induced by cellulose sponge.

METHODS

In ten burn patients, after excision, a test area was divided into three sections: One transplanted with STSG instantaneously and two sections had a pre-treatment for 2 weeks with either DT or a cellulose sponge inducing granulation tissue formation and thereafter grafted with STSGs.

RESULTS

One week after grafting, the STSGs on GT demonstrated most endothelial CD31⁺ staining, largest average vessel diameters as well as most CD163⁺ staining of M2-like macrophages and most MIB1⁺ proliferating epidermal cells, suggesting an active regenerative environment. STSGs on DT had smallest vessel diameters and the least CD163⁺ macrophages. STSGs on EX had the least CD31⁺ cells and the least MIB1⁺ proliferating cells. After 3 months, this reactivity in STSGs had subsided, except increased dermal cell proliferation was observed in STSGs on EX.

CONCLUSIONS

Results show that pre-treatment of wound bed and induction of granulation tissue formation can accelerate host-graft interaction by stimulating graft vasculature and inducing cell proliferation.

VEGF Receptor-2 Activation Mediated by VEGF-E Limits Scar Tissue Formation Following Cutaneous Injury

Objective: Vascular endothelial growth factor (VEGF) family members are critical regulators of tissue repair and depending on their distinct pattern of receptor specificity can also promote inflammation and scarring. This study utilized a receptor-selective VEGF to examine the role of VEGF receptor (VEGFR)-2 in scar tissue (ST) formation. Approach: Cutaneous skin wounds were created in mice using a 4 mm biopsy punch and then treated until closure with purified VEGF-E derived from orf virus stain NZ-2. Tissue samples were harvested to measure gene expression using quantitative PCR and to observe ST formation through histological examination and changes in cell populations by immunofluorescence. Results: VEGFR-2-activation with VEGF-E increased expression of anti-inflammatory cytokine interleukin (IL)-10 and reduced macrophage infiltration and myofibroblast differentiation in wounded skin compared with controls. VEGF-E treatment also increased microvascular density and improved pericyte coverage of blood vessels in the healing wounds. The ST that formed following treatment with VEGF-E was reduced in size and showed improved collagen structure. Innovation: The role of VEGFR-2 activation in wound epithelialization and angiogenesis is well established; but its contribution to ST formation is unclear. This study tests the effect of a selective VEGFR-2 activation on ST formation following cutaneous wounding in a murine model. Conclusion: VEGFR-2 stimulation can enhance the quality of skin repair, at least, in part, through the induction of IL-10 expression and dampening of wound inflammation and fibrosis. Therapies that selectively activate VEGFR-2 may therefore be beneficial to treat impaired healing or to prevent excess scarring.

Where's the Leak in Vascular Barriers? A Review

Edema is typically presented as a secondary effect from injury, illness, disease, or medication, and its impact on patient wellness is nested within the underlying etiology. Therefore, it is often thought of more as an amplifier to current preexisting conditions. Edema, however, can be an independent risk factor for patient deterioration. Improper management of edema is costly not only to the patient, but also to treatment and care facilities, as mismanagement of edema results in increased lengths of hospital stay. Direct tissue trauma, disease, or inappropriate resuscitation and/or ventilation strategies result in edema formation through physical disruption and chemical messenger-based structural modifications of the microvascular barrier. Derangements in microvascular barrier function limit tissue oxygenation, nutrient flow, and cellular waste removal. Recent studies have sought to elucidate cellular signaling and structural alterations that result in vascular hyperpermeability in a variety of critical care conditions to include hemorrhage, burn trauma, and sepsis. These studies and many others have highlighted how multiple mechanisms alter paracellular and/or transcellular pathways promoting hyperpermeability. Roles for endothelial glycocalyx, extracellular matrix and basement membrane, vesiculo-vacuolar organelles, cellular junction and cytoskeletal proteins, and vascular pericytes have been described, demonstrating the complexity of microvascular barrier regulation. Understanding these basic mechanisms inside and out of microvessels aid in developing better treatment strategies to mitigate the harmful effects of excessive edema formation.

Biventricular differences in β-adrenergic receptor signaling following burn injury

Burn injury detrimentally affects the myocardium, primarily due to over-activation of β-adrenergic receptors (β-AR). Autopsy reports from our institution reveal that patients often suffer from right ventricle (RV) failure. Since burn injury affects β-AR signaling in the left ventricle (LV), we proposed that β-AR signaling may also be altered in the RV. A rodent model with a scald burn of 60% of the total body surface area was used to test this hypothesis. Ventricles were isolated 7 days post-burn. We examined the expression of β-ARs via Western blotting and the mRNA expression of downstream signaling proteins via qRT-PCR. Cyclic adenosine monophosphate (cAMP) production and protein kinase A (PKA) activity were measured in membrane and cytosolic fractions, respectively, using enzyme immunoassay kits. β₁-AR protein expression was significantly increased in the RV following burn injury compared to non-burned RV but not in the LV (p = 0.0022). In contrast, β₂-AR expression was unaltered among the groups while G_αi expression was significantly higher in the LV post-burn (p = 0.023). B-arrestin-1 and G-protein coupled receptor kinase-2 mRNA expression were significantly increased in the left ventricle post-burn (p = 0.001, p<0.0001, respectively). cAMP production and PKA activity were significantly lower in the LV post-burn (p = 0.0063, 0.0042, respectively). These data indicate that burn injury affects the β-AR signaling pathway in the RV independently of the LV. Additionally, non-canonical β-AR signaling may be activated in the RV as cAMP production and PKA activity were unchanged despite changes in β₁-AR protein expression.

Pyruvate in oral rehydration salt improves hemodynamics, vasopermeability and survival after burns in dogs

BACKGROUND

To investigate whether pyruvate-enriched oral rehydration solution (Pyr-ORS), compared with citrate-enriched ORS (Cit-ORS), improves hemodynamics and organ function by alleviating vasopermeability and plasma volume loss during intra-gastric fluid rehydration in dogs with severe burn.

METHODS

Forty dogs subjected to severe burn were randomly divided into four groups (n=10): two oral rehydrated groups with Pyr-ORS and Cit-ORS (group PR and group CR), respectively, according to the Parkland formula during the first 24h after burns. Other two groups were the intravenous (IV) resuscitation (group VR) with lactated Ringer's solution with the same dosage and no fluid rehydration (group NR). During the next 24h, all groups received the same IV infusion. The hemodynamics, plasma volume, vasopermeability and water contents and function of various organs were determined. Plasma levels of vascular endothelial growth factor (VEGF) and platelet activating factor (PAF) were detected by ELISA.

RESULTS

Hemodynamics parameters were significantly improved in group PR superior to group CR after burns. Levels of VEGF and PAF were significantly lower in group PR than in group CR. Organ function parameters were also greatly preserved in group PR, relative to groups CR and NR. Lactic acidosis was fully corrected and survival increased in group PR (50.0%), compared to group CR (20.0%).

CONCLUSION

Pyr-ORS was more effective than Cit-ORS in improving hemodynamics, visceral blood perfusion and organ function by alleviating vasopermeability-induced visceral edema and plasma volume loss in dogs with severe burn.

Ultrasound ablation enhances drug accumulation and survival in mammary carcinoma models

Magnetic resonance-guided focused ultrasound (MRgFUS) facilitates noninvasive image-guided conformal thermal therapy of cancer. Yet in many scenarios, the sensitive tissues surrounding the tumor constrain the margins of ablation; therefore, augmentation of MRgFUS with chemotherapy may be required to destroy remaining tumor. Here, we used 64Cu-PET-CT, MRI, autoradiography, and fluorescence imaging to track the kinetics of long-circulating liposomes in immunocompetent mammary carcinoma-bearing FVB/n and BALB/c mice. We observed a 5-fold and 50-fold enhancement of liposome and drug concentration, respectively, within MRgFUS thermal ablation-treated tumors along with dense accumulation within the surrounding tissue rim. Ultrasound-enhanced drug accumulation was rapid and durable and greatly increased total tumor drug exposure over time. In addition, we found that the small molecule gadoteridol accumulates around and within ablated tissue. We further demonstrated that dilated vasculature, loss of vascular integrity resulting in extravasation of blood cells, stromal inflammation, and loss of cell-cell adhesion and tissue architecture all contribute to the enhanced accumulation of the liposomes and small molecule probe. The locally enhanced liposome accumulation was preserved even after a multiweek protocol of doxorubicin-loaded liposomes and partial ablation. Finally, by supplementing ablation with concurrent liposomal drug therapy, a complete and durable response was obtained using protocols for which a sub-mm rim of tumor remained after ablation.

Blumea balsamifera Oil for the Acceleration of Healing of Burn Injuries

Blumea balsamifera oil (BBO) is a main extract obtained from Blumea balsamifera (L.) DC (Ainaxiang) leaves, which are widely used as a traditional medicine by the Miao and Li Nations to promote skin trauma or burn injury healing. This study was initiated to investigate the healing efficacy in deep second-degree burn model in rats. The rats were treated by BBO for 21 consecutive days. The rate of healing, scabs dropped time and re-epithelialization time were observed every three days for 21 days after burn injury. The samples were collected from different treated rats by sacrificing the animals on the 1st, 2nd, 5th, 9th, 14th, and 21st day post-burn creation. Then, the water content of burn tissue was measured. Plasma interleukin-1 (IL-1) and tumor necrosis factor-alpha (TNF-α) levels were evaluated, and the tissue expressions of basic fibroblast growth factor (bFGF), vascular endothelial growth factor (VEGF), and transforming growth factor-beta (TGF-β) were determined along with skin histopathology. The results showed that the water content of tissue was significantly reduced, the scabs dropped time shortened, and healing accelerated after treatment with BBO in the burn injury rats. Furthermore, the expressions of growth factors were significantly increased in the tissue; however, the levels of inflammatory factors on plasma decreased. This study confirms the efficacy of BBO consumption on burn injuries.

A double-edged sword: the role of VEGF in wound repair and chemoattraction of opportunist pathogens

Wound healing is a complex process essential to repairing damaged tissues and preventing infection. Skin is the first line of defense, a chief physical barrier to microbe entry. Wound healing is a physical rebuilding process, but at the same time it is an inflammatory event. In turn, molecules for wound repair are secreted by fibroblasts and others present at the wound site. Vascular endothelial growth factor (VEGF) is a critical cytokine that exhibits chemoattractant properties, recruiting other immune cells to the site. Although generally beneficial, VEGF may also act as a chemoattractant for invading microorganisms, such as Pseudomonas aeruginosa.P. aeruginosa is problematic during wound infection due to its propensity to form biofilms and exhibit heightened antimicrobial resistance. Here, we explored the influence of VEGF gradients (in a microfluidic device wound model) on the motility and chemotactic properties of P. aeruginosa. At lower concentrations, VEGF had little effect on motility, but as the maximal concentration within the gradient increased, P. aeruginosa cells exhibited directed movement along the gradient. Our data provide evidence that while beneficial, VEGF, in excess, may aid colonization by P. aeruginosa. This highlights the necessity for the efficient resolution of inflammation. Understanding the dynamics of wound colonization may lead to new/enhanced therapeutics to hasten recovery.

Anti-vascular endothelial growth factor therapy in breast cancer

Neo-angiogenesis is a critical process for tumor growth and invasion and has become a promising target in cancer therapy. This manuscript reviews three currently relevant anti-angiogenic agents targeting the vascular endothelial growth factor system: bevacizumab, ramucirumab and sorafenib. The efficacy of anti-angiogenic drugs in adjuvant therapy or as neo-adjuvant treatment has been estimated in clinical trials of advanced breast cancer. To date, the overall observed clinical improvements are unconvincing, and further research is required to demonstrate the efficacy of anti-angiogenic drugs in breast cancer treatments. The outcomes of anti-angiogenic therapy have been highly variable in terms of tumor response. New methods are needed to identify patients who will benefit from this regimen. The development of biomarkers and molecular profiling are relevant research areas that may strengthen the ability to focus anti-angiogenic therapy towards suitable patients, thereby increase the cost-effectiveness, currently estimated to be inadequate.

Negative pressure wound therapy decreases mortality in a murine model of burn-wound sepsis involving Pseudomonas aeruginosa infection

Background

The colonization of burn wounds by Pseudomonas aeruginosa can lead to septic shock, organ injuries, and high mortality rates. We hypothesized that negative pressure wound therapy (NPWT) would decrease invasion and proliferation of P. aeruginosa within the burn wound and reduce mortality.

Methods

Thermal injuries were induced in anesthetized mice, and P. aeruginosa was applied to the wound surface for 24 h. After removing the burn eschar and debridement, the animals were subjected to either NPWT or wet-to-dry (WTD) treatment protocols. The bacterial loads on the wound surface were assessed during 7 d of treatment, as were the concentrations of inflammatory cytokines in the peripheral blood samples. Survival was monitored daily for 14 d after burn induction. Finally, samples of wounded skin, lung, liver, and kidney were collected and subjected to histopathological examination.

Results

Applying P. aeruginosa to the burn wound surface led to sepsis. During early stages of treatment, NPWT reduced the mortality of the septic animals and levels of P. aeruginosa within the burn wound compared with WTD-treated animals. Circulating levels of cytokines and cytoarchitectural abnormalities were also significantly reduced via NPWT.

Conclusions

Our data indicate that NPWT inhibits the invasion and proliferation of P. aeruginosa in burn-wounded tissue and decreases early mortality in a murine model of burn-wound sepsis. These therapeutic benefits likely result from the ability of NPWT to decrease bacterial proliferation on the wound surface, reduce cytokine serum concentrations, and prevent damage to internal organs.

In vivo inhibition of hypertrophic scars by implantable ginsenoside-Rg3-loaded electrospun fibrous membranes

Clinically, hypertrophic scarring (HS) is a major concern for patients and has been a challenge for surgeons, as there is a lack of treatments that can intervene early in the formation of HS. This study reports on a Chinese drug, 20(R)-ginsenoside Rg3 (GS-Rg3), which can inhibit in vivo the early formation of HS and later HS hyperplasia by inducing the apoptosis of fibroblasts, inhibiting inflammation and down-regulating VEGF expression. Implantable biodegradable GS-Rg3-loaded poly(l-lactide) (PLA) fibrous membranes were successfully fabricated using co-electrospinning technology to control drug release and improve drug utilization. The in vivo releasing time of GS-Rg3 lasts for 3 months, and the drug concentration released in rabbits can be controlled by varying the drug content of the electrospun fibers. Histological observations of HE staining indicate that GS-Rg3/PLA significantly inhibits the HS formation, with obvious improvements in terms of dermis layer thickness, epidermis layer thickness and fibroblast proliferation. The results of immunohistochemistry staining and Masson's trichrome staining demonstrate that GS-Rg3/PLA electrospun fibrous membranes significantly inhibit HS formation, with decreased expression of collagen fibers and microvessels. VEGF protein levels are much lower in the group treated with GS-Rg3/PLA eletrospun membranes compared with other groups. These results demonstrate that GS-Rg3 is a novel drug, capable of inhibiting the early formation of HS and later HS hyperplasia. GS-Rg3/PLA electrospun membrane is a very promising new treatment for early and long-term treatment of HS.

Biomarkers for anti-angiogenic therapy in cancer

Angiogenesis, the development of new vessels from existing vasculature, plays a central role in tumor growth, survival, and progression. On the molecular level it is controlled by a number of pro- and anti-angiogenic cytokines, among which the vascular endothelial growth factors (VEGFs), together with their related VEGF-receptors, have an exceptional position. Therefore, the blockade of VEGF signaling in order to inhibit angiogenesis was deemed an attractive approach for cancer therapy and drugs interfering with the VEGF-ligands, the VEGF receptors, and the intracellular VEGF-mediated signal transduction were developed. Although promising in pre-clinical trials, VEGF-inhibition proved to be problematic in the clinical context. One major drawback was the generally high variability in patient response to anti-angiogenic drugs and the rapid development of therapy resistance, so that, in total, only moderate effects on progression-free and overall survival were observed. Biomarkers predicting the response to VEGF-inhibition might attenuate this problem and help to further individualize drug and dosage determination. Although up to now no definitive biomarker has been identified for this purpose, several candidates are currently under investigation. This review aims to give an overview of the recent developments in this field, focusing on the most prevalent tumor species.

Prognostic and predictive value of serum vascular endothelial growth factor (VEGF) in squamous cell carcinoma of the head and neck

INTRODUCTION

This study aimed to investigate the prognostic and predictive value of serum vascular endothelial growth factor (VEGF) in head and neck squamous cell carcinoma (HNSCC).

METHOD

Preoperative and 6-month postoperative serum VEGF levels were measured using a quantitative sandwich enzyme immunoassay technique in 55 consecutive patients with HNSCC and two control groups. The first control group included normal, healthy, age- and sex-matched individuals (n = 20), while the second control group included the patients who had history of HNSCC and were free of disease for at least 5 years (n = 25).

RESULTS

The mean baseline serum VEGF concentrations of the 55 patients with HNSCC and the first and the second control groups were 437.86, 42.56, and 48.03 pg/ml, respectively (P < 0.001). After a median follow-up of 75 months, 15 patients of the study group developed recurrent disease and 40 patients remained free of disease. The mean preoperative and 6-month postoperative serum VEGF levels for the 40 patients who did not have recurrent disease were respectively 327.69 and 153.50 pg/ml compared to 731.72 and 692.96 pg/ml for the 15 patients with recurrent disease (P < 0.001). High (≥540 pg/ml) serum VEGF level was associated with poor overall survival (P < 0.001). Moreover, multivariate analysis showed node stage (P < 0.001) and preoperative serum VEGF level (P = 0.020) as significant, independent prognostic factors for overall survival.

CONCLUSION

Preoperative or postoperative elevated serum levels of VEGF are highly predictive for disease recurrence and are associated with poor disease-free and overall survival of patients with HNSCC.

Capillary leak syndrome in trauma: what is it and what are the consequences?

TICS is a complex disease that is clearly multifactorial in the traumatically injured patient (Fig. 2). Although systemic inflammation that occurs directly as a result of injury plays the most prominent role, the local tissue and organ injury effects of trauma not only cause local capillary leak and edema but also further amplify the SIRS response. High volume fluid administration and hypoproteinemic states further exacerbate the problem. All of this leads to organ dysfunction and failure, which is the third leading cause of death following injury. Strategies to treat TICS and attenuate its effects once it occurs by targeting inflammatory pathways have been wholly unsuccessful. The mainstay of therapy for TICS is prevention and minimization of its lethal effects. Newer resuscitation strategies such as hemostatic resuscitation and early goal-directed therapies are currently the best available strategies to combat TICS. Whether these result in better outcomes remains to be seen and the authors anxiously await the results of well-designed prospective trials.

Local and systemic treatments for acute edema after burn injury: a systematic review of the literature

Burn injury is a complex trauma that results in local and generalized edema. Edema fluid limits the exchange of vital nutrients in healing the burn wound and will compromise vulnerable tissues. Although the importance of edema control in tissue salvage is recognized, treatments targeted at edema control have not been critically reviewed. Thus, the objective was to assess the evidence for the effectiveness of local and systemic treatments for edema management immediately after burn injury. Searches for randomized controlled trials were conducted of online databases, research and thesis registers, and grey literature repositories. Handsearches included journals, bibliographies, and proceedings. Authors were contacted to clarify and submit extra study details. Eight studies were included. Management of acute major burn resuscitation including colloid increases lung edema (mean difference [MD], 0.04 ml/ml alv vol; 95% confidence interval [CI], 0.03-0.04; P < .00001) and mortality (risk ratio, 3.67; 95% CI, 1.16-11.58; P = .03). Continuous administration of vitamin C in acute burn resuscitation reduces local wound edema (MD, -3.50 ml/g; 95% CI, -4.63 to -2.37; P < .00001) and systemic fluid retention (MD, -8.60 kg; 95% CI, -13.47 to -3.73; P = .0005). Local acute hand burn edema is reduced (MD, -29.00 ml; 95% CI, -53.14 to -4.86; P = .02), and active hand motion increased (MD, 10.00°; 95% CI, 4.58-15.42; P = .0003), using electrical stimulation with usual physiotherapy. Each review outcome was based on a small single-facility study. Thus, future research in intervention for acute burn edema must focus on multicentre trials and validation of outcome measures in the burn population.

How and why does the proteome respond to microgravity?

For medical and biotechnological reasons, it is important to study mammalian cells, animals, bacteria and plants exposed to simulated and real microgravity. It is necessary to detect the cellular changes that cause the medical problems often observed in astronauts, cosmonauts or animals returning from prolonged space missions. In order for in vitro tissue engineering under microgravity conditions to succeed, the features of the cell that change need to be known. In this article, we summarize current knowledge about the effects of microgravity on the proteome in different cell types. Many studies suggest that the effects of microgravity on major cell functions depend on the responding cell type. Here, we discuss and speculate how and why the proteome responds to microgravity, focusing on proteomic discoveries and their future potential.

Blood levels, apoptosis, and homing of the endothelial progenitor cells after skin burns and escharectomy

BACKGROUND

Skin burns are an acute trauma involving an extensive vascular damage and an intense inflammatory response. Bone marrow-derived circulating endothelial progenitor cells (EPC) are known to migrate to sites of neovascularization in response to mediators (vascular endothelial growth factor and stromal cell-derived factor-1) released after trauma and ischemia, to contribute to wound healing, and to increase neovascularization of animal prefabricated flaps. Recent data showed an increase in EPC number in burned patients and a positive correlation between EPC number and total body surface area (TBSA) burnt, but data were limited to the first 5 days after thermal injury.

METHODS

By using flow cytometry, we studied EPC (CD34, CD133, CD45, and KDR cells) blood levels, apoptosis, and homing (stromal cell-derived factor-1 receptor expression and CXC chemokine receptor 4) in a 1-month follow-up postburn in 25 patients with ≥15% TBSA burnt, at least grade II burns and escharectomy performed at days 5 to 6, with respect to 31 controls.

RESULTS

EPC count at admission showed a positive linear correlation with TBSA burnt. The EPC blood levels of the patients were low (50.7 cells/mL±61.8 cells/mL) immediately after thermal injury, then increased with two peaks, at day 1 (188.3 cells/mL±223.2 cells/mL) and day 12 (253.1 cells/mL±430.7 cells/mL) with respect to controls (95.2 cells/mL±28.5 cells/mL, p<0.05), and then returned to normal levels in 1 month. EPC apoptotic rate and inflammatory parameters paralleled EPC blood count. No significant variations were found in CXC chemokine receptor 4 expression.

CONCLUSIONS

Thermal injury and escharectomy seem to induce an intense response in EPC production. In particular, escharectomy could improve physiologic wound repair by increasing EPC levels.

The impact of vascular endothelial growth factor and basic fibroblast growth factor on cardiac fibroblasts grown under altered gravity conditions

BACKGROUND

Myocardium is very sensitive to gravitational changes. During a spaceflight cardiovascular atrophy paired with rhythm problems and orthostatic intolerance can occur. The aim of this study was to investigate the impact of basic fibroblast growth factor (bFGF) and vascular endothelial growth factor (VEGF) on cardiac fibroblasts (CF) grown under altered gravity conditions.

METHODS

We examined the influence of exposure to a Random Positioning Machine (RPM) on CF, derived from porcine hearts. We focused on growth, extracellular matrix protein (ECMP) synthesis and apoptosis.

RESULTS

When cultured on a RPM, CF began to form 3D spheroids within 24h, irrespective of growth factor treatment. Exposure to RPM induced an increased synthesis of ECMP and also resulted in elevated apoptosis in adherent CF as measured by terminal deoxynucleotidyl transferase-mediated dUTP digoxigenin nick end labeling (TUNEL) analysis, 4',6-diamidino-2-phenylindole (DAPI) staining, and caspase-3 detection. bFGF and VEGF significantly decreased the amount of ECMP (collagen type I, III, chondroitin sulfate) in 1g and RPM cultures, and also significantly reduced the amount of apoptotic CF as well as caspase-3.

CONCLUSIONS

Altered gravity conditions on a RPM induced 3D growth, elevated ECMP synthesis and apoptosis in cardiac fibroblasts. Growth factor treatment attenuated programmed cell death and ECMP secretion.

Sepsis in burns: a review of current practice and future therapies

Sepsis is a major cause of death worldwide and remains the subject of much research and debate within the critical care community. Despite advances in burn prevention, treatment, and rehabilitation, sepsis remains a common cause of death in patients who have sustained a severe burn injury. The unique physical, metabolic, and physiologic changes seen after major thermal injury mean that the management of sepsis in burns poses a particular challenge and differs in many respects to the management of sepsis in the general critical care population. This article describes current issues in the prevention, diagnosis, and treatment of sepsis in burns with a review of the associated literature. In addition, we discuss possible future therapies for managing this condition.

Different responsiveness of endothelial cells to vascular endothelial growth factor and basic fibroblast growth factor added to culture media under gravity and simulated microgravity

When incubated under simulated microgravity (s-microg), endothelial cells (EC) form tubular structures that resemble vascular intimas. This delayed formation of 3D EC structures begins between the 5th and 7th day of culturing EC under conditions of s-microg, when double-row cell assemblies become visible. With the aim of learning about this initial phase of tubular structure formation, we found that NFkappaBp65 protein content was similar in all cell populations, but gene and protein expression of phosphokinase A catalytic subunit, phosphokinase Calpha, and extracellular signal-regulated kinases 1 and 2 was altered in cells cultured under s-microg. Apoptosis remained below 30% in all EC cultures. In contrast to controls, the 7-day-old s-microg cultures contained 3D aggregates with proliferating cells, enhanced numbers of necrotic cells, and osteopontin-negative EC as well as supernatants with reduced quantities of vascular endothelial growth factor (VEGF), basic fibroblast growth factor (bFGF), soluble TNFRSF5, TNFSF5, intercellular adhesion molecule-1, tumor necrosis factor receptor 2, IL-18, complement C3, and von Willebrand factor. VEGF and/or bFGF (10 ng/mL) application influenced the accumulation of proteins in supernatants more profoundly under 1 g than under s-microg. These findings provide evidence that phosphokinase Calpha plays a key role in tube formation. Improving the interaction of VEGF and/or bFGF with EC under s-microg could enhance the engineering of vascular intimas.

Synchronized changes in serum vascular endothelial growth factor during the clinical course of chronic systemic capillary leak syndrome

Systemic capillary leak syndrome (SCLS) is a rare disease characterized by leakage of plasma from blood vessels into the interstitial space due to increased capillary permeability. We describe a 24-year-old man who was hospitalized with systemic edema, hypoalbuminemia, and disseminated intravascular coagulation. After extensive investigative procedures, he was diagnosed with chronic SCLS and made a gradual recovery after starting on prednisolone, terbutaline, and theophylline. We measured the patient's serum vascular endothelial growth factor (VEGF) over time and found a relationship between serum VEGF and the clinical course.

Potential cellular and molecular causes of hypertrophic scar formation

A scar is an expected result of wound healing. However, in some individuals, and particularly in burn victims, the wound healing processes may lead to a fibrotic hypertrophic scar, which is raised, red, inflexible and responsible for serious functional and cosmetic problems. It seems that a wide array of subsequent processes are involved in hypertrophic scar formation, like an affected haemostasis, exaggerated inflammation, prolonged reepithelialization, overabundant extracellular matrix production, augmented neovascularization, atypical extracellular matrix remodeling and reduced apoptosis. Platelets, macrophages, T-lymphocytes, mast cells, Langerhans cells and keratinocytes are directly and indirectly involved in the activation of fibroblasts, which in turn produce excess extracellular matrix. Following the chronology of normal wound healing, we unravel, clarify and reorganize the complex molecular and cellular key processes that may be responsible for hypertrophic scars. It remains unclear whether these processes are a cause or a consequence of unusual scar tissue formation, but raising evidence exists that immunological responses early following wounding play an important role. Therefore, when developing preventive treatment modalities, one should aim to put the early affected wound healing processes back on track as quickly as possible.

Polydeoxyribonucleotide improves angiogenesis and wound healing in experimental thermal injury

OBJECTIVE

Polydeoxyribonucleotide contains a mixture of nucleotides and interacts with adenosine receptors, stimulating vascular endothelial growth factor expression and wound healing. The purpose of this study was to investigate the effect of polydeoxyribonucleotide on experimental burn wounds.

DESIGN

Randomized experiment.

SETTING

Research laboratory at a university hospital.

SUBJECTS

Thermal injury in mice.

INTERVENTIONS

Mice were immersed in 80 degrees C water for 10 secs to achieve a deep-dermal second-degree burn. Animals were randomized to receive either polydeoxyribonucleotide (8 mg/kg/day intraperitoneally for 14 days) or its vehicle alone (0.9% NaCl solution at 100 microL/day intraperitoneally). On days 7 and 14 the animals were killed. Blood was collected for tumor necrosis factor-alpha measurement; burn areas were used for histologic and immunohistochemical examination, for the evaluation of vascular endothelial growth factor and nitric oxide synthases by Western blot, and for the determination of wound nitric oxide products.

MEASUREMENTS AND MAIN RESULTS

Polydeoxyribonucleotide increased burn wound re-epithelialization and reduced the time to final wound closure. Polydeoxyribonucleotide improved healing of burn wound through increased epithelial proliferation and maturation of the extracellular matrix as confirmed by fibronectin and laminin immunostaining. Polydeoxyribonucleotide also improved neoangiogenesis as suggested by the marked increase in microvessel density and by the robust expression of platelet-endothelial cell adhesion molecule-1. Furthermore, polydeoxyribonucleotide blunted serum tumor necrosis factor-alpha and enhanced inducible nitric oxide synthase and vascular endothelial growth factor expression and the wound content of nitric oxide products.

CONCLUSIONS

Our study suggests that polydeoxyribonucleotide may be an effective therapeutic approach to improve clinical outcomes after thermal injury.

Angiopoietin-2, marker and mediator of endothelial activation with prognostic significance early after trauma?

OBJECTIVE

To measure plasma levels of angiopoietin-1 (Ang-1), angiopoietin-2 (Ang-2), and vascular endothelial growth factor (VEGF) early after trauma and to determine their clinical significance.

BACKGROUND

Angiopoietins and VEGF play a central role in the physiology and pathophysiology of endothelial cells. Ang-2 has recently been shown to have pathogenetic significance in sepsis and acute lung injury. Little is known about the role of angiopoietins and VEGF early after trauma.

METHODS

Blood specimens from consecutive major trauma patients were obtained immediately upon arrival in the emergency department and plasma samples assayed for Ang-1, Ang-2, VEGF, markers of endothelial activation, protein C pathway, fibrinolytic system, and complement. Base deficit was used as a measure of tissue hypoperfusion. Data were collected prospectively.

RESULTS

Blood samples were obtained from 208 adult trauma patients within 30 minutes after injury before any significant fluid resuscitation. Plasma levels of Ang-2, but not Ang-1 and VEGF were increased and correlated independently with severity of injury and tissue hypoperfusion. Furthermore, plasma levels of Ang-2 correlated with markers of endothelial activation, coagulation abnormalities, and activation of the complement cascade and were associated with worse clinical outcome.

CONCLUSIONS

Ang-2 is released early after trauma with the degree proportional to both injury severity and systemic hypoperfusion. High levels of Ang-2 were associated with an activated endothelium, coagulation abnormalities, complement activation, and worse clinical outcome. These data indicate that Ang-2 is a marker and possibly a direct mediator of endothelial activation and dysfunction after severe trauma.

Mobilization of endothelial progenitor cells into the circulation in burned patients

BACKGROUND

Bone marrow-derived endothelial progenitor cells (EPCs) have been detected in the peripheral blood of patients following thermal injury. EPCs migrate to sites of active neovascularization in response to mediators released after trauma, contributing to wound healing. The aim was to characterize levels and kinetics of EPCs in burned patients, then relate these to key mobilizing factors, vascular endothelial growth factor (VEGF) and the chemokine (C-X-C motif) ligand 12 (CXCL 12), and compare them with those in healthy subjects.

METHODS

The study included 19 adult patients with superficial or full-thickness burns and 50 blood donor volunteer controls. EPCs, identified by cell surface markers CD45(dim/-), CD133+, CD144+ and VEGF receptor 2, were quantified by four-colour flow cytometry. Plasma VEGF and CXCL12 were measured using enzyme-linked immunosorbent assay.

RESULTS

Burned patients showed a rapid rise in EPC levels within 24 h, a ninefold increase compared with controls, returning to basal levels by 72 h. Body surface area burned correlated strongly with the degree of mobilization. EPC levels correlated significantly with rises in plasma VEGF and CXCL12.

CONCLUSION

Thermal injury induced a rapid rise in EPCs that was proportional to the extent of the burn and significantly correlated with levels of angiogenic cytokines. Such cytokines may be used to stimulate EPCs as a future therapeutic target in burned patients.

Aerosolized anticoagulants ameliorate acute lung injury in sheep after exposure to burn and smoke inhalation

OBJECTIVE

Acute lung injury is a detrimental complication for victims of burn accidents. Airway obstruction plays an important role in pulmonary dysfunction in these patients. In this study, we tested the hypothesis that aerosolized anticoagulants will reduce the degree of airway obstruction and improve pulmonary function in sheep with severe combined burn and smoke inhalation injury by preventing the formation of airway fibrin clots.

DESIGN

Prospective, randomized, controlled, experimental animal study.

SETTING

Investigational intensive care unit at a university hospital.

SUBJECTS

Adult female sheep.

INTERVENTIONS

After 7 days of surgical recovery, sheep were given a cutaneous burn (40% of total body surface, third degree) and insufflated with cotton smoke (48 breaths, <40 degrees C) under halothane anesthesia. After injury, sheep were placed on ventilators and resuscitated with lactated Ringer's solution. Sheep were randomly divided into five groups: sham, noninjured and nontreated (n = 6); control, injured and aerosolized with saline (n = 6); recombinant human antithrombin (rhAT) + heparin, injured and aerosolized with rhAT (290 units for each) and heparin (10,000 units for each) (n = 6); rhAT, injured and aerosolized with rhAT alone (290 units for each; n = 5); and heparin, injured and aerosolized with heparin alone (10,000 units for each; n = 5). rhAT and heparin were aerosolized every 4 hrs, starting at 2 hrs postinjury.

MEASUREMENTS AND MAIN RESULTS

Cardiopulmonary hemodynamics were monitored during a 48-hr experimental time period. Control sheep developed multiple signs of acute lung injury. This pathophysiology included decreased pulmonary gas exchange and lung compliance, increased pulmonary edema, and extensive airway obstruction. These variables were stable in sham animals. The aerosolization of rhAT or heparin alone did not significantly improve deteriorated pulmonary gas exchange. However, aerosolization of these anticoagulants in combination significantly attenuated all the observed pulmonary pathophysiology.

CONCLUSIONS

The results provide definitive evidence that aerosolized rhAT and heparin in combination may be a novel treatment strategy for pulmonary pathology in burn victims with smoke inhalation injury.